In the case of known controls for escalators the drive is switched off when the escalator is unused. If passengers approach the escalator, a signal is triggered, for example by crossing a light barrier, and the drive is switched on. After expiry of a predetermined period of time, at the earliest after the last passenger has left the escalator, the drive is again switched off.
A control system for drives of escalators has become known from, for example, U.S. Pat. No. 1,985,563, in which columns with a light barrier are arranged at the entrance to the escalator. If a passenger goes through the light beam then the escalator, which is stationary in the unused state, is switched on.
In the case of the afore-described solution the light barrier is arranged at a spacing from the escalator on separate columns. This requires an additional and unnecessary cost for materials and installation. Moreover, a passenger does not necessarily pass through the light barrier. A person who does not know the control system and approaches the stationary escalator from the side can, by going around the light barrier, walk onto the escalator without it being switched on. This can invoke the disadvantageous impression of a defective or unreliable escalator.
In addition, indicating and information equipment for an escalator has become known from EP 0 621 225, which equipment is installed in the balustrade. The panel-like equipment is detachably connected with the balustrade. This equipment contains several components, such as light barriers, indicating elements, etc. Avoidance of the barrier by a mode of operation as described above is not possible. If a passenger walks onto the stationary escalator and interrupts the light barrier at the height of the handrail deflection the drive would thereby be switched on. In this case, however, there is created an unpleasant, possibly even risky—and thereby unreasonable to the passenger—state, since the approaching passenger already stands on the steps of the escalator when it is switched on. Moreover, in this solution as well an additional panel is necessary in order to accommodate components, such as the light barrier. This panel additionally diminishes the visual impression of the balustrade, which possibly consists of glass, and offers virtually no protection against vandalism.
Patent EP 0 847 956 shows light sensors which are arranged in the region of handrail deflection, with transmitters and receivers which monitor the entire space in front of the escalator. This device is unobtrusive, but still visible, and for that reason not completely vandal-proof. Moreover, the light sensors are misdirected by weather influences and triggered in the case of, for example, direct receipt of sunlight. Such sensors also require large and expensive amplifiers and an electronic evaluating system and cannot recognize the direction of a movement. Persons who, for example, go onto the escalator and those who leave the escalator are treated in the same manner. When escalators are arranged in parallel, it often happens that persons departing one escalator erroneously cause starting up of another escalator.